1. Technical Field
This invention relates to fiber optic systems and, more particularly, to a fiber optic connector.
2. Discussion
Fiber optic cables are used in a wide variety of systems. These applications range from low power systems in areas such as illumination and communications, to high power systems such as laser surgery and laser firing units While fiber optic cables are relatively efficient transmitters of electromagnetic energy, significant losses in transmission efficiency can occur at interface points. These interface points may occur where two separate cables are connected, or where a cable is terminated and light enters or exits a cable from adjacent devices.
There are many reasons for significant losses at the interfaces. Among these include the loss of light due to divergence or spreading of light rays exiting an optical fiber For example, where it is desired to couple the light from one optical fiber to another, the divergence of the light rays upon exiting one optical fiber will cause some light to miss the adjacent optical fiber. Diffraction of the exiting light rays will cause a similar effect.
Transmission losses may also be caused by misalignment of the coupled optical fibers or by lack of perpendicularity of the terminal face of the fibers. These situations may cause transmission losses by causing some light rays to miss the receiving fiber, or to be reflected by the receiving fiber. Another cause of transmission losses at optical fiber interfaces is contamination by dust or other particles which will absorb the transmitted light. Accordingly, it is important that a fiber optic connector maintain the fiber ends in close proximity, and in accurate alignment.
Besides transmission losses, a number of other problems are frequently encountered at fiber optic couplings. Because of the forces applied to optical fibers at the coupling during coupling and decoupling, damage to the optical fiber is frequently experienced at or near the coupling. To minimize damage to optical couplings by forces applied during handling, an effective means of strain relief is necessary. In addition, damage to the fiber can be caused during mating and demating by contact with the adjacent coupling if the couplings are misaligned during mating.
The above problems are even more acute in high power optical fiber applications. In such applications light losses become critical because any stray light may cause damage to the optical fiber connector itself. For example, such stray light may melt the adjacent connector material. Not only may such melting compromise the structural integrity of the connector, but the melted material can deposit itself on the optical fiber and cause further transmission losses. This is usually catastrophic in high power applications because any contamination on the face of the optical fiber will absorb the light energy, heat up, and seriously damage the optical fiber. In particular, when high power laser pulses in the range of 425 milliJoules (mJ) are transmitted through conventional optical fiber couplers (such as G and H, Part No. 211133), damage frequently occurs for the above described reasons. An additional problem with conventional fiber optic connectors is that while it is important to inspect and clean fiber optic faces at coupling points, the geometry of the coupler frequently makes cleaning and inspecting the fiber optic face difficult.
In view of the above problems, it would be desirable to provide an optical fiber coupling device which minimizes transmission losses even at high power. In addition, it would be desirable to provide an optical fiber coupler which aligns the two fibers to be coupled in very close proximity while keeping the optical fiber faces perpendicular. In addition, it would be desirable to provide an optical fiber connector having a geometry such that even where light does escape and melt surrounding connector material, this melted material will not reach the optical fiber faces.
Further, it would be desirable to provide such an optical fiber connector that can be mated and demated repeatedly without damage to the fibers. It would further be desirable to provide an optical fiber coupler which incorporates strain relief to prevent damage to he optical fiber during handling. Also it would be desirable to provide an optical fiber coupler which would permit cleaning and inspecting of the optical fiber faces with relative ease.